I’ve provided IT support and training over several decades and also wrote software reviews about recovery software and other useful applications for business users. I’ve taken an in-depth look at TestDisk to let you know how likely it is to recover your lost data.
I conclude that most users will find TestDisk difficult to use. It’s a text-based command-line tool like those commonly found on a DOS-based computer in the 1980s. The lack of a graphical user interface will feel foreign, and the software offers little help or explanation and assumes a high degree of computer literacy.
In this TestDisk review, I’ll explore the types of data the application can restore, how long this is likely to take, and weigh up your chance of success. Let’s get started.
TestDisk is a free data recovery tool designed to recover lost partitions and make non-booting disks bootable again. The software can repair faults caused by faulty software, viruses, and human error, but not when the hardware itself is failing.
The primary use of this software is repairing and restoring partitions rather than recovering accidentally deleted files. While it can do both, the company’s other product, PhotoRec, is more appropriate for the second task.
Both applications are distributed under the free software GPL v2+ license which means that you can use the software free of charge and share it with others. Versions for a number of operating systems can be downloaded from the official website:
- Windows (from XP on) and Windows server (from 2003 on)
- BSD (FreeBSD, NetBSD, OpenBSD)
- Sun Solaris
In this review, we’ll cover the macOS version. Mac users running recent versions of macOS will need the 64-bit version of the software, and this can only be installed using the Homebrew package manager.  That confirms that this is a tool aimed at tech-savvy users.
How is data recovery possible? When you delete a file it is not actually removed from the folder or drive that contains it. It’s simply marked as being deleted and the space it occupies is now available.
In time, as you create new files, both the directory entry and data are likely to be overwritten. That means that data recovery is never guaranteed, and acting as early as possible will offer the best chance of success.
Methods of data recovery offered:
- Undelete files from FAT, exFAT, NTFS, and ext2 file systems on Windows and Linux computers
- Copy files from deleted partitions (including Windows formats such as FAT, exFAT, NTFS, and ext2/ext3/ext4 Linux formats)
- Partition table recovery to fix damaged or deleted partitions
- Recover the boot sector of FAT32 and NTFS drives from a backup
- Rebuild boot sectors of FAT12, FAT16, FAT32, and NTFS drives
- Fix FAT (file allocation) tables
Supported file systems: TestDisk can find lost partitions on a wide range of file systems, including some that are rare and unusual:
- BeFS (used for the rare BeOS operating system)
- BSD disklabel (used with FreeBSD, OpenBSD, and NetBSD)
- CramFS, a compressed file system
- DOS/Windows FAT12, FAT16, and FAT32
- Xbox FATX
- Windows exFAT
- HFS, HFS+ and HFSX, Hierarchical File System
- JFS, IBM’s Journaled File System
- Linux btrfs
- Linux ext2, ext3, and ext4
- Linux GFS2
- Linux LUKS encrypted partition
- Linux RAID md 0.9/1.0/1.1/1.2
- RAID 1: mirroring
- RAID 4: striped array with parity device
- RAID 5: striped array with distributed parity information
- RAID 6: striped array with distributed dual redundancy information
- Linux Swap (versions 1 and 2)
- LVM and LVM2, Linux Logical Volume Manager
- Mac partition map
- Novell Storage Services NSS
- NTFS (used by Windows NT/2000/XP/2003/Vista/2008/7)
- ReiserFS 3.5, 3.6 and 4
- Sun Solaris i386 disklabel
- Unix File System UFS and UFS2 (Sun/BSD/…)
- XFS, SGI’s Journaled File System
- Wii WBFS
- Sun ZFS
TestDisk is a text-based application you run from the command line. For example, on a Mac, you open the Terminal app and type sudo testdisk. The application does not offer a graphical user interface and will feel old-fashioned and difficult to use for most users.
Scanning for lost files can be time-consuming. How fast is TestDisk? I used it to scan for lost partitions on a 4 GB flash drive on my iMac and the time taken was 25 minutes. That’s quite a bit slower than other data recovery tools that took between four and ten minutes.
Data recovery can never be guaranteed. How successful is TestDisk? User satisfaction is high. CNET gave the TestDisk (and PhotoRec) a rating of 4.3 stars based on 23 user votes.  Many users had success when using the software, but not all. Data recovery can never be guaranteed—in time, the lost data will be overwritten.
G2 also gave the application a high rating of 4.2 stars, but this was based on only five reviews and all were either four or five stars.  One Linux user called the software “simple but powerful”, but I can’t imagine many Windows and Mac users would call it “simple”. Many users claim that it successfully recovered their data.
The official TestDisk website offers step-by-step guides on how to use the software as well as a comprehensive 60-page PDF. Support can be obtained from other users on the TestDisk Forum and the developer seems quite active there. 
Is TestDisk safe?
Yes. The software contains no malware or third-party software, and scans will not overwrite any data.
Is TestDisk really free?
Yes. The GPL v2+ license (GNU General Public License) means that you can use and distribute the software free of charge.
If TestDisk isn’t right for you, here are some alternatives I recommend.
R-Studio is another advanced tool capable of recovering files and partitions and is effective in a range of data loss scenarios. It’s suitable for data recovery professionals and is available for both Windows and Mac.
Data Recovery makes data recovery simple by offering an easy-to-use wizard that will scan your drive quickly for lost files. It’s available for both Windows and Mac.
Stellar is an easy-to-use application with a wide variety of features. It is a reliable and effective application, but its scans can be time-consuming. It’s available on both Windows and Mac.
TestDisk will appeal only to advanced users who are comfortable using the command line and text-only software. Based on a limited number of user reviews it seems to effectively recover lost files and partitions, but non-technical users are likely to find the software difficult to use.
There are quite a few easy-to-use alternatives that require no technical knowledge for data recovery, like those listed above. They are not free but are a much better choice for most users. A free trial will show whether your data can be recovered so that you can purchase the software with peace of mind.